Positive displacement vapor control apparatus for fluid transfer

ABSTRACT

In the transfer of fluids and particularly liquids between vessels at the same or different pressures defining a closed system, e.g., from one container to another, e.g., from an underground gasoline tank to a car gas tank, the loss of vapors is a hazard to health and safety and a prominent environmental problem. This invention provides a positive displacement arrangement for removing accumulated vapors from the receiving tank, usually, using the energy of the incoming liquid, for transfer back to the supply tank to eliminate loss of vapors to the atmosphere.

United States Patent 1 1 Hamilton Nov. 26, 1974 1 1 POSITIVE DISPLACEMENT VAPOR CONTROL APPARATUS FOR FLUID TRANSFER [76] Inventor: Chester C. Hamilton, 904

Westminister Ave, Alhambra, Calif. 91803 [22] Filed: Mar. 3, 1972 [21] Appl. No.: 231,580

[52] US. Cl 141/59, 141/290, 417/348 [51] Int. Cl B65b 31/00 [58] Field of Search 141/44, 45, 46, 52, 53, 141/54, 59, 198229, 290, 65; 417/348, 349;

[56] v References Cited UNITED STATES PATENTS '9/1959 Wolf et al. 141 290 1/1962 Brandt 141 59 x 5/1965 Milonas et al. 222/484 X 3,198,126 8/1965 Minich 417/348 X 3,581,782 6/1971 Onufer.... 3,686,893 8/1972 Edwards 3,710,831 1/1973 Riegel 141/52 X Primary Examinerl louston S. Bell, Jr. Assistant ExaminerFrederick R. Schmidt [5 7 ABSTRACT In the transfer of fluids and particularly liquids be tween vessels at the same or different pressures defining a closed system, e.g., from one container to another, e.g., from an underground gasoline tank to a car gas tank, the loss of vapors is a hazard to health and safety and a prominent environmental problem. This invention provides a positive displacement arrangement for removing accumulated vapors from the receiving tank, usually, using the energy of the incoming liquid, for transfer back to the supply tank to eliminate loss of vapors to the atmosphere.

2 Claims, 5 Drawing Figures if 3 3g/; 13

/ .-l a l POSITIVE DISPLACEMENT VAPOR CONTROL APPARATUS FOR FLUID TRANSFER BACKGROUND OF THE INVENTION This invention has to do with improvement of the environment and specifically with apparatus to minimize or eliminate a substantial source of the addition of hydrocarbon and other vapors to the atmosphere and more generally to a closed system fluid transfer arrangement which operates independently of pressure disparities in the system.

The loss of gasoline vapors at filling stations as each car gas'tank is filled is enormous over a day in any metropolitan area. Other, less apparent sources of hydrocarbon vapor loss which also contribute to the problem are transfers from bulk carriers to filling station underground tanks, bulk plant losses as the carrier trucks are filled, all providing gasoline loss, and numerous other transfers of fluids, e.g., volatile liquids, such as halohydrocarbons and alkanes up to carbon atoms and the like and solvents in dry cleaning, and industrial cleaning, and degreasing operations.

In each of these instances the liquid vaporizes to some extent in transfer and these vapors go off into the atmosphere where they can be smog generating.

PRIOR ART In the past, the concern over loss of vapors has been economic, i.e., it was a cost to the liquid owner. See US. Pat. No. 1,269,639 to Parr. At the present time, the ever-increasing hazard of smog has refocused concorn for hydrocarbon and like vapor losses on the health and ecology problem, primarily,

SUMMARY OF THE INVENTION More particularly, the invention provides, for use in a closed system wherein fluid is transferred from a fluid supply via a fluid transfer conduit to a location wherein vapor accumulates and mixes with air, the combination comprising a vapor withdrawal conduit communicating with the accumulated vapor and air mixture for passage thereof out of contact with fluid in the fluid transfer conduit to a remote collection point, and means beyond said location to effect flow of the vapor-airmixture along the vapor conduit in proportion to fluid transfer to the collection point. The invention contemplates a chamber defining the location, such as a fluid I receiving tank, and a fluid supply tank containing the fluid supply adapted forfluid flow communication with the receiving tank through the fluid transfer conduit. The supply tank may additionally define the remote collection point and the vapor withdrawal conduit then provides communication between the receiving tank and the supply tank for vapor passage to the supply tank, where means may be provided to separate mixture air from the supply tank. The means to effect vapor flow may comprise a positive displacement mechanism operated to simultaneously pump fluid through the fluid transfer conduit and to pump the vapor-air mixture through the vapor conduit in a predetermined ratio.

In another aspect of the invention, the positive displacement mechanism is responsive to flow of fluid in the fluid transfer conduit to pump the vapor-air mixture. The mechanism may be operated by flow of fluid in the fluid transfer conduit to displace a volume of vapor along the vapor conduit proportional to the volume of fluid flowing in the fluid transfer conduit, the vapor being passed countercurrently to the fluid under the force of the positive displacement mechanism and independent of the relative pressures in the supply and receiving vessels. The positive displacement mechanism typically comprises a pump structure including a casing with first and second circumferentially spaced cavities and rotor means arranged to move through the cavities. The liquid transfer conduit includes the first cavity to drive the rotor by liquid flow through the conduit. The vapor withdrawal conduit includes the second cavity for rotor induced vapor displacement through the vapor conduit.

A pump housing is generally provided to mount the pump rotor and to define the cavities and enclosing the mechanism and liquid and vapor conduit portions in open communication with the first and second cavities respectively and means to connect the housing to the receiving tank in sealed relation.

The receiving tank may be provided with a filling neck and the apparatus then may also include a fitting projecting from the housing and defining continuations of the liquid and vapor conduit portions, the fitting being adapted for insertion into said filling neck in fluid tight relation. The conduit portions continuations may be relatively differently extended to have the liquid transfer conduit project relatively more into said neck.

In preferred embodiments, the first and second cavities are eccentrically shaped and diametrically opposed across the rotor, the rotor comprising a hub extending between the cavities in sealing relation with the housing and having plural radial slotsand vanes projecting from the slots in guided relation and independently variably in response to the cavity shaping as the rotor turns. The apparatus may also include handle means for carrying the housing, valve means controlling flow through the liquid transfer conduit and a lever adjacent the handle for manually actuating the valve.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be further described as to an illustrative embodiment in conjunction with the attached drawings in which:

FIG. 1 is a schematic view of a filling station application of the invention to which the present invention is highly adapted;

FIG. la is a fragmentary detail view of the downstream terminus of the vapor conduit tube shown immersed in FIG. 1; 1

FIG. 2 is a view generally in vertical section of a gasoline delivery nozzle modified to incorporate the multiple conduits and pump of the invention;

FIG. 3 is a transverse section taken on line 33 in FIG. 2; and

FIG. 4 is an elevational view of the nozzle sealably inserted into a gas tank filling neck shown in section.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention will now be described with reference to the attached drawings wherein a filling station usage of the invention is depicted. A filling station embodiment is used because of the general familiarity nearly all persons have with such facilities and the significance of the cumulative vapor and liquid loss problem at these ubiquitous installations. It is to be remembered, of course, that such usage is only typical and that numerous other transfer systems may be improved in their environmental factor by the applications of the apparatus herein described, for example, industrial solvent users, dry cleaning establishments, bulk chemical processors, transportation transfer points, fleet garages, gasoline, diesel fuel, and solvent loading facilities and like liquid transfer locations. In addition, the principles of the invention may be applied for dust or other particulate contaminant control in various pumpable liquid or solid product handling systems. With reference to FIG. 1, a car 1 on concrete pad 2 is shown receiving gas through hose 3 from pump 4 on island 5. The gas is stored below ground 6 in supply tank 7 and is delivered upward to the pump 4 through pipe 8. A vapor return pipe 9, having porous terminus 10 is shown entering the tank 7 and extending below the surface level 11 of gasoline 12 therein. The porous terminus 10 of return pipe 9 as shown more clearly in FIG. 1a, permits distributed release or sparging of the returned vapor into the stored gasoline, required for combustible liquids.

Referring now to FIG. 4, the hose 3 is seen to comprise two independent conduits 13, 14 for liquid inflow and vapor outflow respectively, as will be explained, which enter the nozzle 15 from the rear and communicate, without mixing of their liquid and vapor, with conduit extensions 13a, 14a which are inserted into filling neck 16 of gasoline receiving tank 17. It will be observed that the liquid carrying conduit extension 13a extends relatively more into the filling neck 16 so that the vapor withdrawal conduit extension 14a is free to immersion in the tank liquid 18 for purposes of vapor withdrawal. The conduits 13, 14 and/or their extensions 13a, 14a may be side-byside, as shown, or one within another, e.g. concentrically, if desired, with the vapor conduit extension 14a being the outer member.

As noted above, the present apparatus provides a positive displacement of vapor from the receiving tank 17. Advantageously, this is accomplished by pump means, e.g., by vane pump 19, the power to operate which is derived from the flow of liquid to the receiving tank 17. Other sources of power may be used. Referring now to FIGS. 2 and 3 the nozzle 15 is shown with liquid conduit 13 and vapor conduit 14 entering the rear of nozzle housing 20.

Within the housing 20, a continuation of liquid conduit- 13 is provided in the form of a flow path comprising inlet passage 21, a first cavity 22 a tubular passage 23 communicating directly with conduit extension 13a. Similarly, the housing defines a continuation of the vapor withdrawal conduit 14 in the form of a countercurrent flow path comprising tubular passage 24 communicating directly with the vapor conduit extension 14a, second cavity 25 and outlet passage 26 into which conduit 14 is connected. I

Liquid flow through the nozzle 15 is controlled by valve 27 in passage 23 in a generally known manner, the valve 27 comprising a valve seat 28 across the passage 23, a valve body 29, a stem actuator 30 for the valve and spring 31 arranged to bias the valve closed. A lever 32 is provided for manually actuating the valve body 29 by vertically moving the stem 30.

Within the pump chamber 33 is provided the vane pump 19. Forming a sea] at 34 between the diametrically opposed first and second cavities 22, 25 is the rotor hub 35 of the pump mounted on shaft 36 which is j'ournaled in the housing 20. The rotor hub 35 is cylindrical and provided with radially extending, equidistantly spaced slots 37 into which variably extendible vanes 38 are slidably mounted against compression springs 39 seated in the slots. The cavities 22 and 25 are eccentric as is common in vane pumps of this type and arranged to guide extension and return of the vanes passing therethrough. Webs 40 are provided at the passages 21, 23, 24, 26 to limit extension of the vanes in passing these passages.

In operation, the lever 32 is raised, opening valve 27 and completing the liquid flow path through the hous- 2 ing 20 for flow of gasoline from conduit 13 to passage 21, through first pump chamber cavity 22, passage 23 and into receiving tank 17 through conduit continuation 13a. As the liquid passes through cavity 22 the motor side of the rotor hub 35 is turned by the force of liquid on extended vanes 38. Opposite these driven vanes in cavity 22, other vanes in cavity 25 are moved by the pump side of the rotor hub 35 and act toevacuate the cavity 25. The vacuum produced thereby at 43 draws vapors from location 41 into the cavity 25 along the vapor flow path explained above and as these vapors pass through the cavity 25 they are displaced progressively farther along vapor conduit 14 by successive rotor hub revolution until the vapors are sparged into the supply liquid through terminus 10. At this point, the relationship between the liquid removed from and the vapor returned to the supply tank 7 will be noted. Because of the liquid removal, the return of vapor is eased and less power is needed to drive the vapor back to the supply tank 7, relative to other possible collection points. Moreover, the relative volumes of liquid and vapor can be varied by varying the relative volume proportions of the cavities 22 and 25. Also, the nozzle pump may be operated on motive power provided by the incoming liquid and only when liquid is flowing, which is a considerable economic advantage.

The nozzle 15 is typical of various types of spouts and connectors and is desirably sealed in the filler neck 16 by means such as annular seal 42 to ensure a closed system.

The supply tank 7 may be maintained at a pressure equal to or relatively greater or less than the receiving tank pressure. Air mixed with the vapor may be removed from the supply tank through pressure adjustment port 44 either to a tank truck for central processing to ensure release of only uncontaminated air to the atmosphere or to other equipment (not shown) for separating contaminants prior to release.

I claim:

1. In combination with a closed system including pump means for forcibly transferring a vaporizable liquid from a liquid supply tank at a variable flow rate via a liquid conduit to a liquid receiving chamber in which vapor of said liquid has accumulated, which system includes a vapor conduit communicating with said accumulated vapor and providing passage thereof out of contact with liquid in said liquid transfer conduit from said chamber to said supply tank;

positive displacement fluid metering means connected in series relation with said vapor conduit and drivable at variable drive speed for displacing vapor effectively positively along said vapor conduit toward said supply tank at a rate proportional to said drive speed and substantially independent of the relative pressures normally existing in the receiving chamber and the supply tank, and positive displacement rotary means connected in series with said liquid conduit for deriving rotary movement proportional to the rate of liquid flow therein and for driving said metering means at a drive speed proportional to said rotary movement,

whereby said volume of vapor displaced toward said supply tank maintains a predetermined proportion to the volume of liquid flowing to said receiving chamber, substantially independently of the rate of said liquid flow.

2. Combination according to claim 1 in which said rotary means comprise a casing defining a first cavity connected in series with said liquid conduit, and vaned rotor means arranged for vane movement through the cavity for deriving rotor movement at a speed proportional to the volume of liquid flowing through the cavity, said rotor means comprising a hub and vanes movable radially of the hub and forming with the cavity wall chambers which vary positively in volume by virtue of said vane movements,

and said metering means comprise a second cavity formed between said casing and said'rotor means and arranged for vane movement therethrough, said second cavity being connected in series with said vapor conduit, vane movement through said second cavity displacing through the cavity a volume of vapor proportional to the rotor speed, l= =i l 

1. In combination with a closed system including pump means for forcibly transferring a vaporizable liquid from a liquid supply tank at a variable flow rate via a liquid conduit to a liquid receiving chamber in which vapor of said liquid has accumulated, which system includes a vapor conduit communicating with said accumulated vapor and providing passage thereof out of contact with liquid in said liquid transfer conduit from said chamber to said supply tank; positive displacement fluid metering means connected in series relation with said vapor conduit and drivable at variable drive speed for displacing vapor effectively positively along said vapor conduit toward said supply tank at a rate proportional to said drive speed and substantially independent of the relative pressures normally existing in the receiving chamber and the supply tank, and positive displacement rotary means connected in series with said liquid conduit for deriving rotary movement proportional to the rate of liquid flow therein and for driving said metering means at a drive speed proportional to said rotary movement, whereby said volume of vapor displaced toward said supply tank maintains a predetermined proportion to the volume of liquid flowing to said receiving chamber, substantially independently of the rate of said liquid flow.
 2. Combination according to claim 1 in which said rotary means comprise a casing defining a first cavity connected in series with said liquid conduit, and vaned rotor means arranged for vane movement through the cavity for deriving rotor movement at a speed proportional to the volume of liquid flowing through the cavity, said rotor means comprising a hub and vanes movable radially of the huB and forming with the cavity wall chambers which vary positively in volume by virtue of said vane movements, and said metering means comprise a second cavity formed between said casing and said rotor means and arranged for vane movement therethrough, said second cavity being connected in series with said vapor conduit, vane movement through said second cavity displacing through the cavity a volume of vapor proportional to the rotor speed. 